Telephone-exchange system.



. J. L. McQUARRlE. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JULY n. ma.

1,292,839. Patented Jan. 28, 1919.

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UNITED STATES PATENT OFFICE.

JAMES L. MGQUARRIE, 0F MONTGLAIR, NEW JERSEY, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Jan. 28, 1919.

Application filed July 11, 1918. Serial No. 244,386.

To all wkomvz't may concern:

Be it known that I, JAMES L. MGQUARRIE, a citizen of the United States, residing at Montclair, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the followlng is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and more particularly to those in which inter-ofiice trunk circuits are employed for completing connections between oflices. In such systems, especially in those in which call wires are not employed in the as signment of trunk circuits, it is desirable that the operator at the outgoing end of the trunk circuit be able to readily determine at any time which trunk circuits are available for use without the necessity of individually testing such circuits. Inasmuch as an indication of this nature is required only when a trunk circuit is being selected, it is desirable to have such indications responsive to operator-controlled means.

It is the object of this invention to provide an improved signaling means for systems of this character.

To. attain this object in accordance with a feature of the invention, individual signaling devices are provided at the outgoing ends of the trunk circuits which are responsive to the actuation of an operator-controlled means. to display signals in connection withthe various idle trunk circuits of a predetermined group..

The nature of the invention will more fully appear from the following specification' and annexed drawing, in which the figure represents, diagrammatically, suflicient portions of a plurality of trunk clrcuits and the associated link or connecting circults to properly illustrate the invention.

In the accompanying drawing jacks 1 represent the outgoing terminals of one trunk circuit multipled at the positions X, Y and Z of a switchboard, while jacks 2 represent similar terminals of a second trunk circuit. A lamp 3 is associated with each of jacks 1 of one trunk circuit and a lamp 4: is associated with eachof jacks 2 of the other trunk circuit. At each position a plurality of suitable link or connecting circuits which may be of any usual type terminating in the plugs 5 are supplied. All portions of the link and trunk circuits which are not essential to the proper understanding of the invention have been omitted and although only two trunk circuits are indicated as appearing at three positions, it is understood that a greater number of trunk circuits may be employed and that these trunk circuits may be multipled to any number of positions. A relay 6 or 7 is included in the sleeve circuit of each trunk circuit and controls a normally closed contact in the circuit of the associated multipled signal lamps 3 or at respectively. At each position a slow release relay 8 controlled by an operator-controlled switch 9 is provided to control normally open contacts in the circuits of the signal lamps 3 and l in that position. Such relays and the associated keys may be common to a group of trunk circuits leading to a certain offioe or may be associated with some other arbitrary group of circuits.

It is thought that the invention will be more fully comprehended from the following description of the operation of the embodiment illustrated on the drawing.

Assuming that the operator at position X desires to select a trunk circuit, the non-locking key 9 located at such position is momentarily actuated to operate relay 8 over a circuit extending from battery through the winding of relay 8 and the contact of key 9 to ground. Lamp 3 at position X is thereby lighted over a circuit extending from battery through the right-hand contact of relay 8,lamp-3, and the contact of relay 6 to ground. Lamp 4 at position X is also lighted over a circuit extending from battery through the left-hand contact of relay 8, lamp 4: and the contact of relay 7 to ground. Although the key 9 is only momentarily actuated, the relay 8 is slow to release so that lamps 3 and at are illuminated for a sufficient time to be readily observed by the operator at position X, who is thereby notified that both of the trunk circuits are idle and available for service. The operator at position X thereupon selects one trunk circuit which may be assumed as being that terminating in jack 1. The consequent insertion of the plug 5 of the link circuit in the jack 1 causes the operation of relay 6 over a circuit established from battery through the sleeve contacts of the plug 5 and jack 1 and the winding of relay 6 to ground.

WVhile the plug 5 and the jack 1 are engaged at position X, let it be assumed that the operator at position Y desires to select a trunk circuit of the same group. The key 9 at position Y is momentarily depressed, thereby operating the associated-relay 8 over a circuit similar to that traced for relay 8 in position X. The closure of the righthand contact of relay 8 causes the lighting of lamp 4 at position Y over a circuit similar to that described for lamp 4 located at position X. The illumination of lamp 4 indicates to the operator at position Y that the associated trunk circuit is disengaged and is available for service. The lamp 3 at position Y, however, is not lighted due to the previous operation of relay 6, as in the previous case. Due to the fact that relay 8 is slow to release the operator at position Y may readily observe the lighted condition of lamp 4 before the release of such relay. The operator thereupon inserts the plug 5 of a link circuit into the jack 2 of the trunk circuit associated with the lamp 4, thereby operating relay 7 over a circuit extending from battery through the sleeve contacts of plug 5 and jack 2 and the wind ing of relay 7 to ground.

If the operator at position Z now desires to select a trunk circuit of the same group, the key 9 at such position is momentarily depressed, causing the operation of the associated relay 8 for a predetermined time as previously described, but since both relays 6 and 7 are operated, neither lamp 3 nor lamp 4 is lighted. The operator at position Z is thereby notified that all trunk circuits of the group are engaged.

In case the operator at position X selects the trunk circuit terminating in jack 2 instead of in jack 1 relay 7 operates upon the insertion of the plug 5 into the jack 2 and the lamp 3 is lighted instead of lamp 4 upon the depression of the key 9 by the operator at position Y when such operator desires to select the trunk circuit.

It will thus be apparent that upon the actuation of the key associated with a particular group of trunk circuits, all lamps associated with the idle trunk circuits in that group are illuminated so that the operator may readil select the trunk circuit to be used.

What is claimed is:

1. A telephone exchange system comprising a group of trunk circuit terminals, a signaling device associated with each terminal, means also associated with each terminal responsive to the engagement of the associated terminal, andimeans cooperating with the first mentioned means to cause the operation of all signaling devices associated with disengaged terminals.

2. A telephone exchange system comprising a group of trunk circuit terminals, a signaling device associated with each terminal, a circuit for each device normally open at one point, means associated with the group of terminals adapted to close the circuit at such point, and means associated with each terminal operable upon the engagement of the associated terminal to open the circuit at another point thereby preventing the operation of the associated signaling device upon the subsequent operation of the means associated with the group.

3. A telephone exchange system comprising a group of trunk circuit terminals, a signaling device associated with each terminal, a relay also associated with each terminal operating upon the engagement of the associated terminal, a common relay for the group of terminals, and an operator controlled key adapted when actuated to operate the common relay thereby operating all signaling devices associated with disengaged terminals.

In witness whereof, I hereunto subscribe my name this 3rd day of July, A. D. 1918.

JAMES L. MQQUARRIE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

